To find the area of the shaded region, we need to find the area of the rectangle and the area of the triangle that has been cut out, and then subtract the area of the triangle from the area of the rectangle.
The area of the rectangle is:
24 inches x 9 inches = 216 square inches
The area of the triangle that has been cut out is:
(1/2) x 5 inches x 18 inches = 45 square inches
So the area of the shaded region is:
216 square inches - 45 square inches = 171 square inches
Therefore, the answer is not one of the choices given.